Relationship Between Body Posture and Lung Fluid Volume Assessed Using a Novel Noninvasive Remote Dielectric Sensing System

Background: The relationship between body posture and lung fluid level has not been quantified thus far. Remote dielectric sensing (ReDS(TM)) is a recently introduced non-invasive electromagnetic-based technology to quantify lung fluid percentage. Methods and Results: ReDS values were measured at different body postures (i.e., sitting, supine, and supine with legs elevated) in a healthy volunteer cohort (n=16; median age 39 years, 69% men, median [interquartile range {IQR}] body mass index 23.3 kg/m(2) [21.0–26.2 kg/m(2)]). In the sitting position, the median ReDS value was 27% (IQR 25–29%). The ReDS value increased significantly in the supine position (median 28%; IQR 27–30%; P=0.009), and increased further upon leg elevation (median 29%; IQR 28–32%; P=0.001). Conclusions: In this proof-of-concept study, the relationship between body posture and lung fluid level was quantitatively validated in a healthy cohort.